[debugger] simplify debug stepping.

src/mips64/builtins-mips64.cc

Index: src/mips64/builtins-mips64.cc
diff --git a/src/mips64/builtins-mips64.cc b/src/mips64/builtins-mips64.cc
index 008b7c25bbfed8481c9f5a9c6338a1c0291a3980..a6155d189d81faa3185e3e26aca2402e572f4e1c 100644
--- a/src/mips64/builtins-mips64.cc
+++ b/src/mips64/builtins-mips64.cc
@@ -705,11 +705,12 @@ void Builtins::Generate_ResumeGeneratorTrampoline(MacroAssembler* masm) {
   // Flood function if we are stepping.
   Label prepare_step_in_if_stepping, prepare_step_in_suspended_generator;
   Label stepping_prepared;
-  ExternalReference step_in_enabled =
-      ExternalReference::debug_step_in_enabled_address(masm->isolate());
-  __ li(a5, Operand(step_in_enabled));
+  ExternalReference last_step_action =
+      ExternalReference::debug_last_step_action_address(masm->isolate());
+  STATIC_ASSERT(StepFrame > StepIn);
+  __ li(a5, Operand(last_step_action));
   __ lb(a5, MemOperand(a5));
-  __ Branch(&prepare_step_in_if_stepping, ne, a5, Operand(zero_reg));
+  __ Branch(&prepare_step_in_if_stepping, ge, a5, Operand(StepIn));
 
   // Flood function if we need to continue stepping in the suspended generator.
   ExternalReference debug_suspended_generator =